首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   282篇
  免费   11篇
  国内免费   2篇
电工技术   22篇
化学工业   90篇
金属工艺   5篇
机械仪表   5篇
建筑科学   2篇
能源动力   18篇
轻工业   27篇
无线电   25篇
一般工业技术   60篇
冶金工业   8篇
原子能技术   7篇
自动化技术   26篇
  2023年   2篇
  2022年   6篇
  2021年   3篇
  2019年   2篇
  2018年   7篇
  2017年   3篇
  2016年   4篇
  2015年   3篇
  2014年   7篇
  2013年   20篇
  2012年   10篇
  2011年   17篇
  2010年   15篇
  2009年   11篇
  2008年   21篇
  2007年   14篇
  2006年   14篇
  2005年   6篇
  2004年   9篇
  2003年   5篇
  2002年   9篇
  2001年   10篇
  2000年   4篇
  1999年   9篇
  1998年   8篇
  1997年   5篇
  1996年   9篇
  1995年   5篇
  1994年   4篇
  1993年   3篇
  1992年   3篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   7篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1980年   7篇
  1979年   6篇
  1978年   2篇
  1977年   5篇
  1976年   1篇
  1975年   1篇
  1972年   1篇
  1971年   1篇
排序方式: 共有295条查询结果,搜索用时 15 毫秒
81.
An altered ambulatory blood pressure (BP) and heart rate (HR) profile is related to chronic kidney disease (CKD) and cardiorenal syndrome. In this study, we examined the effects of aliskiren, when added to angiotensin II type 1 receptor blockers, on ambulatory BP and cardiorenal function in CKD. Thirty-six hypertensive CKD patients were randomly assigned to the aliskiren add-on group (n = 18) or the benazepril add-on group (n = 18). Ambulatory BP and cardiorenal function parameters were measured at baseline and 24 weeks after treatment. Compared with the benazepril group, nighttime systolic BP variability in the aliskiren group was lower after treatment. Albuminuria was decreased in the aliskiren group, but not in the benazepril group. In addition, left ventricular mass index (LVMI) was significantly lower in the aliskiren group than in the benazepril group after treatment. In the aliskiren group, multivariate linear regression analysis showed an association between changes in albuminuria and changes in nighttime systolic BP. Furthermore, there were associations between changes in LVMI and changes in daytime HR variability, as well as between changes in LVMI and changes in plasma aldosterone concentration. These results suggest that aliskiren add-on therapy may be beneficial for suppression of renal deterioration and pathological cardiac remodeling through an improvement that is effected in ambulatory BP and HR profiles.  相似文献   
82.
目前,移动存储设备以及校园网的广泛使用,使得在校园网内产生了ARP攻击,造成了网络的严重瘫痪。本文通过对ARP攻击原理的分析,定位ARP攻击源头,提出校园局域网内有效的防御方法及解决方案。  相似文献   
83.
讲解了C语言与汇编语言相互调用的基本技术,二者结合实现混合编程的方法和在相互调用过程中需注意的一些问题,并给出了应用实例。两者相互调用有效结合,扬长避短,是一种行之有效的程序设计及开发方法。  相似文献   
84.
Both chemical and mechanical damages to porous SiOC film should be minimized in the Cu-CMP (chemical mechanical polishing) process for the 32-45 nm node Cu interconnect process. This paper first discusses chemical damage that occurs during direct CMP on a porous SiOC film. We found that the k-value increase after direct CMP was caused by the surfactants added to the cleaning chemicals to suppress watermark generation on the hydrophobic SiOC film surface. The surfactants assisted water molecule diffusion into the pores by improving the wettability of the film surface. N2 annealing after direct CMP removed moisture inside the pores and restored the k-value increase. Second, the paper discusses low-pressure electro-CMP (e-CMP) technology that we developed to reduce mechanical stress on the porous SiOC film. A high removal rate and good planarization performance were obtained by optimizing the cathode area of the electro-cell and carbon material of the e-CMP pad.  相似文献   
85.
86.
High-dielectric-constant (Ba, Sr)TiO3 [BST] films were deposited by the liquid source chemical vapor deposition (CVD) method. The system consisted of a single-wafer, low-pressure thermal CVD reactor, a vaporizer for liquid source materials, and a shower-type gas nozzle head, giving stable BST film deposition on a 6-in. diam. substrate with uniform thickness and uniform chemical composition ratio. The source materials employed were Ba(DPM)2, Sr(DPM)2, and TiO(DPM)2 dissolved in tetrahydrofuran (THF), resulting in conformal step coverage of BST films at lowered substrate temperatures, where DPM denotes dipivaloylmethanate. Moreover, the two-step deposition technique was developed to restart protrusions formed on BST film surfaces at low temperatures, where the BST films consisted of a buffer layer and a main layer; the buffer layer was a layer about 60 Å thick of CVD-BST film annealed in N2. Thus, the two-step CVD deposition of BST films on Pt and Ru electrodes achieved an equivalent SiO2 thickness of teq ∼ 0.5 nm, a leakage current of JL ∼ 1.0 × 10−8 A/cm2 (at +1.1 V), and a dielectric loss of tan δ ∼ 0.01 at a total film thickness of 250 Å, along with conformal coverage of 80% for a trench with an aspect ratio of 0.65. Then, for BST films deposited on patterned electrodes 0.24 μm wide, 0.60 μm deep, and 0.15 μm high (each spaced by 0.14 μm), the capacitance was demonstrated to be increased without significant deterioration of the leakage current: the capacitance was increased in comparison with that for films on flat electrodes, by a factor corresponding to the increase in surface area due to sidewalls of storage-node-like pattern features. This capacitance increase reflects the most characteristic advantage of CVD, an excellent step coverage on microscopic pattern features. These electrical properties satisfy the specifications for capacitors for Gb-scale dynamic random access memories (DRAMs), giving a storage capacitance of more than 25 fF/cell for a stacked capacitor having a storage node 0.2 to 0.3 μm high. © 1998 Scripta Technica, Electr Eng Jpn, 125(1): 47–54, 1998  相似文献   
87.
The physical state of the blends of radiation-polymerized polyethylene with high-density polyethylene was studied. Only one peak was observed in DSC heating curves of the blends quenched from the melt regardless of the each polymer content. In addition, transparency of the high-density polyethylene was improved by melt blending with radiation-polymerized polyethylene. This is a characteristic of high-density polyethylene and radiation-polymerized polyethylene blends different from high-density and low-density polyethylene blends. A new peak and/or a new shoulder, however, appeared in DSC heating curves of the blends with heat treatment at 110°, 120°, and 125°C. These results suggest that the physical state of the blends quenched from the melt is one where the crystallization of the radiation-polymerized polyethylene is high hindered by the presence of high-density polyethylene. The radiation-polymerized polyethylene may remain mainly in a physical state similar to the melt. The haze value of the blends increased with heat treatment. The increase in the haze is caused by change in physical states, such as growth of spherulites and formation of microcrystals and microvoids, by the heat treatment.  相似文献   
88.
Divertible proofs are extensions of interactive proofs in which an active eavesdropper, the warden, makes the prover and the verifier untraceable. The warden is transparent to both the prover and the verifier. With subliminal-free proofs the warden controls subliminal messages. In this paper we present divertible and subliminal-free zero-knowledge proofs for various languages. We consider both graph isomorphism and Received September 1992 and revised September 1995 and May 1997  相似文献   
89.
Blowing snow at Mizuho station, Antarctica   总被引:2,自引:0,他引:2  
Blowing snow observations were carried out at Mizuho station, Antarctica, from October to November 2000. A blowing snow observation system including snow particle counters, which can sense not only the number of snow particles, but also their diameters, was situated on a 30 m tower. All instruments worked correctly and the data obtained revealed profiles of mass flux and particle size distributions as a function of the friction velocity. Measurements were compared with a blowing snow model that accounted for most physical processes including aerodynamic entrainment, grain/bed collisions, wind modification, particle size distribution and turbulent fluctuations on the particle trajectories. Simulated and measured results showed close agreement, and the validity of the model was demonstrated. Vertical profiles of horizontal mass flux from saltation to suspension, as well as the particle size distributions were expressed precisely, which could not be achieved using the previous models.  相似文献   
90.
The synthesis of benzo [k, l] thioxanthene-3,4-dicarbo-xylic acid-7,7-dioxide is described. Condensation of this heterocycle with amines, or oxidation of the corresponding imides of benzo [k, l] thioxanthene-3,4-dicarboxylic acid, affords a new range of dyes which colour synthetic-polymer fibres, especially polyester, in yellow shades of excellent fastness to light and sublimation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号